Fire shutter for motion-picture machines



July 2, 1929. w. A. KOSKEN FIRE SHUTTER FOR MOTION PICTURE MACHINES Filed July 9. 1925 INVENTOR. M/fio 4 A ane BY .fd fin? N's.

Patented July 2, 1929.

UNITED STATES PATENT OFFICE.

WILHO A. KOSKEN, OF, NEW YORK, N. Y., ASSIGNOR T STEAIDYLITE MOTION PICTURE MACHINE CORPORATION, OF NEW YORK, N. Y., A CORPORATION OF NEW YORK.

FIRE SHUTTER FOR MOTION-PICTURE MACHINES.

Application filed July 9,

This invention is a fire shutter for motion picture machines and the object of the invention is to provide simple and efiicient electrically controlled mechanism'for shutting off light from the film when the machine is not operating, when the film breaks or at other times when it is desirable to exclude the impinging of light rays on the film.

Speaking generally, the invention consists in a suitable flap or closure mounted sothat in normally closed position it will shut off light from the film. Means is associated with the flap for normally maintaining it in such position, but also associated with the flap is electrically operated means, controlled by the motion picture machine with which the device is associated and constituted to maintain the flap in opened position so long as the machine is functioning properly at predetermined speed, but adapted, if the machine appreciably slows down or stops, or if the film breaks, to immediately release the flap to shut off light from the film and thus safeguard said film against ignition by the light beam.

In one of its preferred practical forms, the closure operating mechanism embodies a magnet or solenoid which is energized from a current generator driven by one of the operating parts of the machine or by the film, so that current is supplied to the magnet or solenoid to hold the closure in opened position, so long as the machine isfunctioning properly. In the event, however, that the machine discontinues to functionproperly, the generator fails to supply the current necessary for maintaining the closure in opened position, and said closure immediately moves into its closed position.

The apparatus is so constituted that the normal position of the closure is such as to exclude the light beam from impinging the film and said closure at all times seeks this position. It is positively held from such position by mechanism depending for its operation upon the proper functioning of the projecting machine. Accordingly, any cessation of the normal proper functioning of the ma chine,'as a projector, will result in the immediate exclusion of the light beam from the film. i

In the preferred form of the invention, I preferably associated with the apparatus means for showing the speed of operation of 1925. Serial No. 42,401.

the projecting machine, so that the operator may determine at a; glance the number of exposures per second or minute.

Features of the invention, other than those speclfied, will be apparent from the herein after detailed description and claims, when read in conjunction with the accompanying drawings.

The accompanying drawing illustrates one practical embodiment of the invention, but

the construction therein shown is to be under-' stood as illustrative, only, and not as defining the limits of the invention.

The drawing shows the present invention in a diagrammatic manner.

Referring to the drawings, 1 designates a wallor partition provided with an opening '2 through which a beam of light B passes to the film (not shown) The partition 1 is between the source of light and thefilm and the beam must pass through the opening 2 in or- .der to impinge the film. Pivoted adjacent the partition 2 on a rock shaft or pivot 3 is a flap or closure 4, which is. adapted, when in the dotted line position, to exclude the passage of light from the opening 2, but when retracted to the full line position, to permit'passage of light through such opening.

Associated with the pivot 3 is an operating arm 5, secured by a link 6 to one arm of a lever 7 which is fulcrume d at 8. A spring 9 cooperates with the same arm of said lever and normally draws it into the dotted line position for the purpose of forcing the flap into closed position. With the free end of the lever is associated a magnet or solenoid 10 and for the purpose of illustration a magnet is shown and a screw 11 is shown as threaded through the free end of the lever and cooperating with the core of the magnet in order to obtain desired adjustments. p

The magnet 10 is included in a circuit 12, which also includes ;the source of electric energy 13 and a switch embodying a fixed contact la and a movable contact 15. The movable contact 15 forms the armature of a magnet 16 which is, in turn, included in a circuit 17 associated with and energizedby a generator 18. The coil. 16 and the switch elements 14 and 15 constitute collectively a relay, so functioning that when the coil ,16is energized, it will attract its armature 15 to complete the local circuit 12 by. engagement with the contact 14: and the magnet 10 is encrgized from the source of electrical energy 13.

It is within the purview of this invention to entirely eliminate this relay, as well as the source 13 and to connect the generator 18 directly to the magnet 10, so that the current generated at 18 will be fed to and energize the magnet 10, as will be. fully understood by those skilled in the art. The showing of the drawings is therefore to be understood as purely illustrative.

In accordance with this invention, the generator 18 is driven through any suitable connection, such as a pulley 19 and belt 20 from any suitable operating element of the proj ecting machineof which the partition 1 forms apart. F or the purpose of illustration, the belt 20 is shown as cooperating with a pulley 21 fixed on a shaft 22 and this shaft may be driven either by a roll engaging or cooperating with a film or by any. mechanical operating part of the projecting machine. If it is driven by some mechanical operating part of the machine, it will function to drive the generator 18 and supply current to the magnet 10 through the relay, so long as the speed of such shaft is such as to supply the requisite amount of current to energize the magnet 10 sufficiently to draw the flap into retracted position. Ifthe speed should unduly diminish or the machine stop, the spring 9 will of course overcome the pull of the mag net 10 and the flap will be closed. If the shaft 22 is driven by a film, it will function in the same manner except that if the film breaks, said shaft will immediately stop and the magnet 10 will be immediately deenergized, to effect instantaneous closing of the I find it convenient and highly practical to use as a generator of current a tachometer having associated therewith a speed indicator 18 for the measuring of current generated by the generator in terms of speed. The indicator may be graduated to show feet per second of the travel of the film, so that the 'operator can at a glance the speed at which the film is moving or said indications may show exposures per second or minute as may be desired.

In the foregoing detailed description, the spring 9 has been described as functioning to normally impel the flap into closed position. It will of course be understood that a weight may be used in lieu of the spring or that the parts may be so formed that their own weight will normally impel the flap into closed position. Furthermore, a pivoted flap is illustrated in the drawings, but it is within the purview of this invention to use a sliding closure in lieu of the pivoted fiap.

F or these reasons, the invention is to be understood as fully commensurate with the appended claims.

The generator 18 and the indicating elemcnt 1S constitute collectively an indicating couple which will be referred to as such in the appended claims. u

Having thus fully described the invention, what I claim as new and desire to secure by Letters Patent is 1. In an assembly of the character described, motion picture projecting mechanism, a speed indicating couple including an electric current generator, driven by the projecting mechanism, a closure normally occupying a position to preclude impinging of the light beam on the film, electrically operated means energized from said current generator, and adapted to move the closure out of the path of the beam and to maintain it in such retracted position so long as the proj ecting mechanism is operated above a predetermined minimum speed, and means to auto matically move the closure into a position to intercept the beam when the speed of the projecting mechanism falls below a predetermined minimum.

2. In an assembly of the character described, motion picture projecting mechanism, a speed indicating couple including a current generator driven from the projecting mechanism, a closure, shutter closing means for normally impelling said closure into a position to preclude impinging of the light beam on the film, electrically operable means controlled by the generator for overcoming the shutter closing means to retract the closure and to maintain said closure in retracted position to permit the beam to impinge the film so long as the projecting mechanism is operating in excess of said predetermined minimum. speed. i i 3. In an assembly of the character described, motion picture projecting mechanism embodying a tachometer including an electric current generator driven by the projecting mechanism, and a closure normally occupying a position to preclude impinging of the light beam on the film, in combination with an operating lever connected to the closure, a magnet for moving said operating lever to open the closure, a circuit including said magnet and also including a normally open switch, a magnet for closing said normally open. switch, and a circuit including the last mentioned magnet and energized from the current generator of the tachometer.

4. In an assembly of the character described, motion picture projecting mechanism embodying a tachometer including a current generator driven by the projecting mechanism, a closure normally occupying a position to preclude impinging of a light beam upon the film, in combination with magnetically controlled means for opening the closure to permit the light toimpinge the filn1,and a relay interposed between said magnetically controlled means and the generator of the tachometer and controlled by the picture projecting mechanism in combination with means controlled by electric current from the tachometer to open the closure and permit of the projecting of pictures so long as the tachometer is operating above a predetermined speed.

In testimony whereof I have signed the foregoing specification.

WVILHO A. KOSKEN. 

